There are places in Spain that still manage to surprise even many locals. And then there is Torrevieja’s famous pink lagoon – a place that is now even attracting the attention of NASA. What was long considered little more than a spectacular tourist attraction on the Costa Blanca is now becoming an important research site for scientists searching for clues to past life on Mars.
Spain Expat Press Editorial Team
by Marlon Gallego Bosbach
The reason for this lies quite literally in the colour of the water. Torrevieja’s “Laguna Rosa” is one of the most extraordinary salt lakes in Europe. Depending on the season, the water shimmers in an intense pink, sometimes almost magenta. The lagoon is clearly visible even from space – and this is precisely what has made it interesting to NASA. Astronauts have repeatedly photographed this vast pink surface from the International Space Station (ISS). Today, the lake is considered a potential “Mars analogue” – a terrestrial model that could help scientists understand what potentially habitable environments on the Red Planet may have looked like in the past.
Why the lake is pink
The striking colour is not caused by chemicals or pollution, but by extremophilic microorganisms – organisms capable of surviving in conditions that would be lethal to most forms of life.
A key role is played by the microalga Dunaliella salina. It produces large amounts of beta-carotene to protect itself against intense UV radiation and the extremely high salinity. This pigment is what gives the water its pink to reddish colour. In addition, so-called halophilic archaea – salt-loving microorganisms – also contribute to the effect. They produce reddish pigments as well, further intensifying the vivid colouring.
The salinity of the lagoon is exceptionally high, in some areas significantly exceeding that of the Mediterranean Sea. It is precisely these extreme conditions that make the site so interesting for scientists. Researchers now believe that hypersaline lakes may also have existed on Mars in the past.
What NASA sees in it
Current Mars research is increasingly focused on locations where water may once have existed. Former salt lakes are of particular interest, as salt can preserve biological traces for millions or even billions of years.
The NASA rover “Perseverance” is currently studying regions on Mars where water once evaporated, leaving behind salt deposits. This is where Torrevieja comes into play. Scientists are now using the Spanish lagoon as a comparative model to better understand how microorganisms survive under extreme conditions and what optical signatures such environments produce.
Orbital imagery is particularly valuable in this context. The different colour tones reveal a surprising amount to scientists about the composition of the water, its salinity, and the activity of specific microorganisms. This helps researchers learn what to look for in future satellite images or Mars observations.
In other words, Spain’s pink lagoon is helping NASA to better identify potential signs of past life on Mars.
Right next to it lies a green lake
The region becomes even more fascinating due to a striking contrast. Right next to the pink lagoon lies the much greener La Mata lagoon.
Although the two lakes are only a few kilometres apart, they differ significantly in biological terms. This is mainly due to the lower salinity of La Mata. Different microorganisms dominate there, along with a much higher presence of chlorophyll, which is why the water appears green rather than pink.
For scientists, this direct comparison is extremely valuable. It shows how sensitive such ecosystems are to even the smallest changes. Minor differences in temperature, salinity, or evaporation can already alter the entire microbial composition of a lake.
A natural phenomenon with a centuries-old history
Salt production in Torrevieja has a long tradition. Salt has been produced there since the Middle Ages. Today, the region is one of Europe’s most important salt producers.
Every year, hundreds of thousands of tonnes of salt are extracted there, used among other things in the food industry, as industrial salt, or as road salt in many European countries. The vast salt flats continue to shape the landscape around Torrevieja and have long become part of the region’s identity.
Flamingos, brine shrimp and a fragile ecosystem
The lagoons are also an important protected natural area. They are especially well known for the many flamingos that can regularly be seen there. Their pink colouring is also caused by a diet rich in carotenoids – similar to the microorganisms that give the water its pink hue.
In addition to flamingos, the region is home to numerous other bird species as well as brine shrimp of the genus Artemia. Many migratory birds also use the wetlands as a resting place each year. The entire area is now part of a protected natural park and is internationally recognised as a highly valuable wetland ecosystem.
Climate change could alter the pink wonder
Researchers have been warning for years that the lagoon’s delicate balance is under threat. Rising temperatures, changing rainfall patterns, and increased evaporation could destabilise the ecosystem in the long term.
If salinity levels or the water’s composition were to change too significantly, the very microorganisms responsible for the lake’s famous pink colour could disappear. This would not only put a spectacular natural phenomenon at risk, but also a unique open-air laboratory for international research.
Spain suddenly at the centre of space research
That a salt lake on the Costa Blanca would one day become part of modern Mars research would have been hard to imagine for most people. Yet this is precisely what shows how important extreme environments on Earth have become in the search for extraterrestrial life.
Because the key question today is no longer simply whether there was once water on Mars. Scientists are now primarily trying to determine whether life could once have existed there.
And the answer to that question may, somewhat surprisingly, lie a little closer to Spain’s pink lagoon.
